Thermographic Questions Options

[PBTHHHHT]

Some things are best left unknown. Though I guess it'll be a great plot for some gay porn movie. Again, something I wish not to know or dwell upon. :-P

edit: And no, they were meaning that the firefighters were not wearing boots so their body heat could easily be transferred from their feet (and socks) to the floor.

[Grinder]

We don't who did watch the test? Some female scientists maybe?

[PBTHHHHT]

Now now, try and remember that there's audience of not just females out there who wouldn't mind watching this sort of thing.

[Shrike30]

Hey, most girls I know think firefighters are hot.

Besides, there's some female firefighters... :P

[SL James]

But the vast majority don't look like Diane Farr, or even come close.

[HullBreach]

Ive had a little bit of expeirience with Infra-red (Simalar to thermo, think the black and white FLIR footage you see on those police chase shows) weapon sights courtesy of uncle sam, so I'll chime in a little.

IR sights do operate on the principal of infra-red radiation, which is basically light outside the human visual range that is associated with heat. Now 90% of using one of these things effectively is a basic understanding of how radiant heat behaves, as well as knowing what IR light will and won't pass through. Some examples:

You can see through most fabrics very easily, but it does haze up the details a bit. I remember being able to clearly make out people moving inside a tent from over a mile away, though their light discipline was excellent and I couldn't even make them out on NVG's.

Foiliage is also pretty ineffective at blocking light in this spectrum. Tree trunks will, but bushes and other greenery barely even break it up. I remember being able to tell where one dude had just finished taking a leak before heading back to his fighting hole because I could still see the hot piss running down the tree trunk. Pretty wild.

Depending on the sensitivity/sophistication of the unit (I've handled both 'grunt proof' simple models as well as one scientific insturment grade model) you can aslo tweak the settings to 'acclimatize' its settings to function better in your enviroment. We had one tuned so finely, we could tell you which troops were using their MRE's heater tabs while eating their dinner in their fighting holes (they release some hot vapors when activated).

Now thermo is about 10 steps more complicated, requires more training to use, but it is also a hell of a lot more capable. A well tuned IR unit lets you see hot or cold. A well tuned Thermographic unit lets you see HOW hot or cold a thing is. In game terms, this could be pretty useful in a variety of situations. Folks using thyroid boosters and certain other high-performance bioware will either have higher body tempatures or distinct hot-spots associated with the gear. The footprints on the floor scenario metioned earlier is also possible with this level of gear.

Also note that disturbed earth is easy to spot using this, as the newly exposed earth will generally be cooler. Aircraft can actually spot some heavy vehicle tracks hours after the fact from the warm tracks caused by the intense ground-pressure of their passing.

As for the walls scenario, it comes down to construction materials and insulation, but a player whose been leaning against a wall for 10 minutes will be visible on the other side dead-air space or no, simply due to the radiant nature of heat.

Spent shell casings are very visible in both IR or thermo (I think they're a little easier to spot in the black-and-white IR displays though), as are hot gun barrels. The hot gasses associated with firing tend to dissapate very quickly.

Finally, some chemical compounds that are inherantly unstable (high explosives, particularly cheap soviet bloc ones) are usually slightly warmer than ambient tempature due to the fact that they are essentially decaying.

The important thing to remember here is that its all about contrast. A 98deg F human body in the snow, or even a nice 74deg F office building is easy to spot. They are also easy to spot in a 110deg F metalworks. But stick them in a 98-ish degree F jungle, and they will blend in fairly well.

Also take into account shapes. The part of our brain that processes images is pretty well tuned to spotting people. But once we start to break up their shape a little bit, it gets tougher. Israeli infantry wear lumpy misshaper helmet shrouds for this reason, it breaks up the head-and-shoulders profile most troops insticntually look for (mostly cause thats how our targets are shaped). Simply mottleing and breaking up ones IR pattern with some enhanced camoflage (the new cammies used by the Marines and Army utilize material that does this) goes a long way to hiding ones self.

This is why Thermal/IR systems are used to supplement other systems, as without tons and tons of field usage, they just arent that insinctual to use.

[Fix-it]

I'm guessing this was RECENT equipment Hullbreach?

as in, a year or two?
what generation are they on for NVGs anyway?

I got to play with a pair of 1st gen (god they were bulky)

and 3rd gen (better but still fuzzy) night vision goggles, and I couldn't see to well with 'em...
IR sounds like fun. too bad it's restricted tech we civilian pukes won't get for another few years. and then have to pay an arm leg and left eye for.

[HullBreach]

These are actually availible to the public:

http://elcan.phpinternet.com/www/SPECTER_0_0_Index.htm

But they cost like 12k last time I checked. Hell, I can't even afford regular range time lately, so somthing like thats a wish for if I hit the lotto!

While I was in we were using Gen 3 NV gear, which has gotten much better. Supposedly the next gen stuff will be almost as sharp as normal vision due to some new manufacturing process for the intensifier tubes (which I've always felt were the weak link, give me an IR enhanced CCD instead!).

The thermo and IR stuff was mostly demonstration samples I just happened to be in the right place at the right time to handle. The IR weaponsights are probobly going to be GI issue for crewserve weapons in the near future, so thats good news as it will drive the public prices down some.

[KarmaInferno]

[Moon-Hawk]

Well that's what makes the hunt challenging, what with humans being so squisky and weak. :-)

[SL James]

Please don't tell me you're trying to apply science to an action movie.

[Fix-it]

yeah, you really shouldn't bother with a movie that features an average guy shooting a minigun from the hip.

[KarmaInferno]

Jesse Ventura is not an average guy!

He's Jesse Ventura!

You take that back!


-karma

[LilithTaveril]

/me sets Jesse Ventura on fire.

[Smokeskin]

AFAIK full recoil force from a 5.56 minigun is around 500 newton, or around the effect gravity exerts on 100 pounds. Braced against the hip, a strong guy should be able to handle that.

[RunnerPaul]

[Austere Emancipa...]

It was an M134, so a 7.62mm minigun. Even then, though, at 2000rpm, perhaps even 3000rpm, a big guy would be able to handle the recoil, to an extent -- I don't know about the other peripheral problems of firing such a weapon unmounted. But he certainly wouldn't be able to lug around the 200+lbs of gun, batteries and ammo, assuming he's to fire it for more than 30 seconds.

[SL James]

True, but to be fair Blain fired it in short, controlled bursts. It was Mac who went apeshit and let the thing fire until it ran out of ammo.

[HullBreach]

Ahem.....the mini-gun thing has been well documented as impossible here:

http://world.guns.ru/machine/minigun-e.htm

Scroll down, its towards the bottom. These guys know there shit, I trust what they say.

[Austere Emancipa...]

They make the mistake of assuming that the gun would be set to fire at 6000rpm. The most recent M134 models fire at 3000rpm, the ones from when Predator was filmed mostly fired at either 2000rpm or 4000rpm. At 2000rpm, we're only talking about a bit over twice the recoil of an M240 -- and according to The Gun Zone, the RoF on the Predator M134 "was reduced to 1700 rpm in order to reduce torque and to lower the voltage required to power the motor that rotates the barrels." They're absolutely right about the weight issues, though, and I have no idea how an M134 ejects empties.

[Smokeskin]

Imo the guys who wrote that at guns.ru have very little idea of what sort of force a human can brace themselves against. Even the 120 kg recoil from an M134 shouldn't knock a strong man over if he was properly braced for it.

If they reduced the cyclic rate, then it becomes much more managable. I've fired 7.62 NATO ammo from a 11 kg LMG at 1200 rpm from a standing position, hanging at the hip but with no hip-brace, without a problem. At 1700 rpm, with a heavier weapon and the centripetal stabilation effect from the rotation barrels, recoil would be even less. If you added a hipbrace, I should think you could easily go double that.

[HullBreach]

[HullBreach]

[Austere Emancipa...]

[HullBreach]

A valid point, I got my number confused for a few moments there (I just woke up, still absorbing cafffine).

On a semi-related note, the US Military (I've only seen the Army do it so far) has began using M-134's on top of Hum-Vees. This is kind of an interesting development, as it really provides a crazy level of firepower to respond to an ambush with.

Personally I've always liked the MK-19.